Roger Waters and Nick Mason said they would be willing to reunite as Pink Floyd for a performance at the Glastonbury music festival. Only problem: David Gilmour, the other surviving member of the band, may not be up for it.

Appearing together in London for the opening of a new exhibit on Pink Floyd, the group’s bassist and drummer were asked if they would consider getting back together for one last performance at the annual Glastonbury festival in Somerset, England, according to The Telegraph.

“It would be nice to add it to the list of things. I’ve never played Glastonbury,” Mason said. “It would be fun to do it. … [But] I don’t think it would be very likely.” “I did Glastonbury once,” Waters added. “I think. It was really cold. But there were a lot of people and it seemed very jolly and I liked it. Yeah, I would do it again.”

The snag in this scenario? Guitarist and singer Gilmour, who isn’t exactly on friendly terms with Waters since the latter left the group in 1985 after a period of simmering hostility between them. Plus, Waters said, “The last I heard, David had retired.” “I heard he retired, then he seemed to unretire,” said Mason. (Gilmour toured last year in support of his 2015 album, Rattle That Lock)

Gilmour and Mason put together what they called Pink Floyd’s final album, The Endless River, in 2014. The album consisted mostly of leftover tracks from 1994’s The Division Bell sessions and was a tribute to Floyd keyboardist Richard Wright, who died in 2008.

The four members last played together in 2005 at Live 8. In 2011, Gilmour and Mason joined Waters onstage when he played London’s 02 Arena. But two years ago, Gilmour told The Telegraph, “Roger and I don’t particularly get along. We still talk. It’s better than it has been. But it wouldn’t work. People change. Roger and I have outgrown each other, and it would be impossible for us to work together on any realistic basis.”

Waters will be busy this summer nonetheless. He just announced a new album, and has a North American tour starting in May.